1. Field of the Invention
The present invention relates to a semiconductor device having an IGBT (Insulated Gate Bipolar Transistor).
2. Background Art
A semiconductor device having an IGBT is used as a power device of high withstand voltage (600 V or higher). As such a semiconductor device, there has been proposed a semiconductor device wherein an extraction region is placed between a transistor region having the IGBT and a termination region placed around the transistor region (for example, refer to the p-layer 4′ in FIG. 1 of Japanese Patent Application Laid-Open No. 6-21358). By the configuration of the extraction region, redundant carriers (holes) can be extracted during turn-off operation.
In the semiconductor device according to Japanese Patent Application Laid-Open No. 6-21358, lattice defect is introduced into the termination region and the extraction region. Since the carrier concentration during turn-off operation can be lowered thereby, depletion can be easily made, and field intensity can be reduced. Therefore, the current breaking capability during turn-off operation can be improved. The term of current breaking capability used here means the maximum breakable current density without the breakdown of the semiconductor device during turn-off operation.